NAG Library Manual, Mark 29
```/* nag_mv_distance_mat (g03eac) Example Program.
*
* Copyright 2023 Numerical Algorithms Group.
*
* Mark 29.0, 2023.
*
*/

#include <nag.h>
#include <stdio.h>

#define X(I, J) x[(I)*tdx + J]
int main(void) {
Integer exit_status = 0, i, *isx = 0, j, m, n, tdx;
double *d = 0, *s = 0, *x = 0;
char nag_enum_arg[40];
Nag_DistanceType dist;
Nag_MatUpdate update;
Nag_VarScaleType scale;
NagError fail;

INIT_FAIL(fail);

printf("nag_mv_distance_mat (g03eac) Example Program Results\n\n");

/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%" NAG_IFMT "", &n);
scanf("%" NAG_IFMT "", &m);
if (n >= 2 && m >= 1) {
if (!(d = NAG_ALLOC(n * (n - 1) / 2, double)) ||
!(s = NAG_ALLOC(m, double)) || !(x = NAG_ALLOC((n) * (m), double)) ||
!(isx = NAG_ALLOC(m, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
tdx = m;
} else {
printf("Invalid n or m.\n");
exit_status = 1;
return exit_status;
}
scanf("%39s", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
update = (Nag_MatUpdate)nag_enum_name_to_value(nag_enum_arg);
scanf("%39s", nag_enum_arg);
dist = (Nag_DistanceType)nag_enum_name_to_value(nag_enum_arg);
scanf("%39s", nag_enum_arg);
scale = (Nag_VarScaleType)nag_enum_name_to_value(nag_enum_arg);
for (j = 0; j < n; ++j) {
for (i = 0; i < m; ++i)
scanf("%lf", &X(j, i));
}
for (i = 0; i < m; ++i)
scanf("%" NAG_IFMT "", &isx[i]);
for (i = 0; i < m; ++i)
scanf("%lf", &s[i]);

/* nag_mv_distance_mat (g03eac).
* Compute distance (dissimilarity) matrix
*/
nag_mv_distance_mat(update, dist, scale, n, m, x, tdx, isx, s, d, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_mv_distance_mat (g03eac).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Print the distance matrix */

printf("\n");
printf(" Distance Matrix ");
printf("\n");
printf("\n");
printf("    %s\n", "   1       2       3       4");
printf("\n");
for (i = 2; i <= n; ++i) {
printf("%2" NAG_IFMT "     ", i);
for (j = (i - 1) * (i - 2) / 2 + 1; j <= i * (i - 1) / 2; ++j)
printf("%5.2f   ", d[j - 1]);
printf("\n");
}

END:
NAG_FREE(d);
NAG_FREE(s);
NAG_FREE(x);
NAG_FREE(isx);

return exit_status;
}
```